1. Field of the Invention
This invention relates generally to diverter valves and, more specifically, to improvements to diverter valves.
2. Description of the Prior Art
One of the uses of pneumatic conveying lines is to transport materials from one location to another. Often times, at selected intervals, it is necessary to divert the material into bins or secondary pneumatic conveying systems. To switch or divert the material from the pneumatic conveyer line into a second system requires a pneumatic switch which will divert the material to the secondary outlet or system. The switch must also seal the connection points or junctions of the two systems so the material being transported does not escape into the environment. Because of explosion hazards of many types of dust, it is important that no dust escapes from the switch.
A typical prior art diverter valve is shown in the Sebestyen U.S. Pat. No. 2,825,604. Sebestyen rotates a pipe around an axis to direct material to any one of a number of different outlets. An inflatable seal is located at the junction of the pipe to the valve.
British Pat. No. 229,844 shows a similar type of device using a swiveling curved pipe that communicates with other pipes.
German Offenlegungsschrift No. 2,051,177 discloses "a pneumatic conveyer junction cock seal in which the cock plug has one or more sealing pistons forced by the internal pressure into the sealing position against the outlet not in use. Hydraulic or mechanical pressure can be used to force the pistons into position and to lift them clear when the cock is being operated."
French Pat. No. 74-13,252 shows a retractable seal made from soft rubber or plastic which can be used for sealing around pipes or the like.
The Great Britain Pat. No. 1,382,347 shows a pipeline switch in which the material is conveyed either by gravity or pneumatically to any of a plurality of outlet pipes. The unit uses at least one annular inflatable joint to provide a seal between the pipes.
All of these prior art devices are very similar because they rotate the same pipe to any number of different outlets and provide some type of a seal around the outlet. The present invention provides an improvement to diverter valves through a rotor and sealing arrangements that provide a trouble-free, easy-to-use diverter valve.
One of the problems associated with prior art pneumatic switching devices has been the difficulty in obtaining a good seal at the outlet of the valve. In addition, most prior art valves become rather large and require a large area for installation. Still other problems occur because prior art diverting units must withstand tremendous amounts of wear by forces generated by the fast moving and abrasive materials flowing in the conveyer tubes. The internal forces make it difficult to properly seal the pneumatic conveying tubes to the pneumatic switches. In addition, pneumatic and conveying valves require relatively free nonjamming capability to provide a reliable, trouble-free diverter valve. Another disadvantage of prior art valves is that valves come either with right hand output or left hand output and cannot be interchanged. Furthermore, under certain conditions the annular inflatable seals may blow out causing leakage of material from the pneumatic line.